Intersexes

Intersexes are individuals in which the diagnosis of the sex is confused because of congenital anatomical variations.

Occurrence

• In goats and pigs: Most common
• In horses and dogs: Less common
• In sheep and cattle: Occasional
• In cat: Rare

Conditions in Intersexes

• Hermaphroditism
• Abnormalities of the accessory genital organs
• Gonadal dysgenesis
• Freemartinism

Classification

Intersexes may be separated into males or females based on:

• Their genetic sex, either chromosomal or nuclear sex
• Their gonadal sex or presence of ovaries or testes
• Their phenotypic sex or the morphology of their accessory genital organs
• Possibly their hormonal or behavioural sex

Hermaphrodites are usually classified on the basis of gonadal sex as:

1. True hermaphrodites: Presence of both testes and ovaries or ovotestes.
2. Pseudohermaphrodites: Presence of gonads of only one sex.
   • Male pseudohermaphrodites: Phenotypically resemble females but have testes.
   • Female pseudohermaphrodites: Phenotypically resemble males but have ovaries.

1. True Hermaphrodites

True hermaphrodites are rarely seen. Most frequent in swine.

True hermaphrodite has internal genitalia resembling both sexes and external genitalia of an intermediate type that may tend either toward the male or female.

In most cases the genetic sex is female (XX) but it is likely that on further study many of these cases may prove to be mosaics or chimeras produced by nondisjunction and/or other mitotic errors during mitosis early in embryogenesis or dispermic fertilization of an ovum by an X-bearing sperm and a non extruded polar body by a Y-bearing sperm resulting in tissues with variable sex chromosome complements such as: XX/XY, XXY, XXYY or XXXY.

2. Pseudo Hermaphrodites

True hermaphrodites also rarely seen. Intersexes with female gonads and external genitalia resembling the male may be produced by exposure to androgens during embryonic life.

Female or true hermaphrodites with fairly normal external and internal female structures may rarely be fertile since ovulation may occur.